This invention relates to a device and method for diagnosing faults in an electronic control system, and more specifically, to a device for passively sampling, in real-time, the electronic signals exchanged between an electronic control module and electronic system components of a system undergoing diagnosis. The device of the present invention interacts with an associated database and computer system to identify and repair-order prioritize for a system operator, those electronic components which are not operating within predetermined parameters as determined from the sampled electronic signals.
Many modem devices, such as automotive vehicles, now include numerous complex electrical components and one or more associated electronic control modules for monitoring and regulating the various component operations. These components typically replace mechanical devices or regulators with electronically activated mechanisms or sensors which are capable of much more precise operation, leading, in the case of an automotive vehicle, to an increase in engine efficiency and an enhancement of vehicle safety features. For example, modern automotive vehicles now include computer controlled anti-lock braking systems, "smart" automatic transmissions, traction control systems, and even yaw control systems. Additional complex electronic components may also be found in engine management areas such as fuel injection systems, emissions control systems, and the continuous observation of numerous engine operating parameters
Many of these complex electrical components and systems are interconnected between each other and to a centralized electronic control module or ECM. Hence, rather than having a simple wiring harness connecting individual components between a power source and an electrical ground, complex bundles of wires now interconnect components and the electronic control module. With this high degree of component interaction, the identification of malfunctioning components becomes much more difficult, as "troubleshooting" the vehicle electrical system becomes an increasingly difficult and time-consuming task. An electrical failure in one component can now affect the operation of numerous other components, leading technicians to incorrect diagnosis. For example, a grounding failure in the electronic control module itself can result in numerous other electrical components defaulting to a "high" state, giving the appearance of numerous component failures when, in reality, only the ECM has failed.
To facilitate diagnosis and repair of these electrical systems found in modern automotive vehicles and other complex devices such as pumping systems, refrigeration systems, and computer aided manufacturing systems, technicians commonly employ diagnostic devices or "break-out boxes" designed to interconnect between the system electronic control module and device wiring harness. These devices are then configured to supply test signals to individual system components or passively observe their operation, and to receive and display the resulting electrical signals to the repair technician, who must then interpret the results to determine if a particular component has failed. There are a number of drawbacks associated with utilizing current break-out boxes for electronic diagnosis. Due to the large number of vehicles or devices which a technician might service, the break-out box must be reconfigured for each different electronic system to which it is connected. The technician must then take time to determine the appropriate settings for the electronic system, and what signal ranges are considered acceptable for the received electrical signals. This often requires consulting a bound service volume, or the use of software running on a computer installed in the repair shop. Such software, while facilitating the task of the technician by supplying connection information and instructions on how to interpret the results, is static, i.e. it only contains information on the particular vehicles or devices which were on the market at the time the software was written. To remain current, the repair shop is required to continually receive updates to the software which contain the latest system electrical component parameters.
Accordingly, it would be advantageous to employ a passive diagnostic system capable of automatically configuring itself to the appropriate settings for a wide variety of vehicles or other systems employing complex electronics which may be tested, and which is also capable of interpreting data received from the electronic system. Furthermore, it would be beneficial if the diagnostic system was easy to use, and did not require periodic software updates to be purchased or installed by the operator.